The present invention relates to a method and an apparatus for coating the surface of a target to be processed, such as, a semiconductor wafer and a LCD substrate with a coating solution, such as, a resist solution and a developing solution.
A semiconductor-device manufacturing procedure usually involves a developing process in which a resist solution, for example, is applied on a semiconductor wafer or a LCD substrate (called a wafer hereinafter) to form a resist film thereon which is then exposed to light through a circuit pattern reduced by photolithography, followed by applying a developing solution on the wafer.
A known coating apparatus such as shown in FIG. 1 is used for applying a developing solution (or a resist solution) on a wafer. The coating apparatus is equipped with a supply nozzle 110 for supplying a developing solution (or a resist solution) on a wafer, a feed pump 160 for feeding a developing solution contained in a developing-solution tank 180 to the supply nozzle 110, a regulator R for regulating the pressure at which the developing solution is supplied from the feed pump 160, a valve V0 through which the developing solution is supplied or seized, a flow meter 125 for measuring the flow rate of the developing solution and a CPU 100 for watching open/close of the valve V0 and the amount of the developing solution while supplied.
The known coating apparatus requires manual operations in which an operator uses a needle to adjust an opening degree of the valve V0, thus opening-degree readjustments being impossible during a coating process. Not only that, the known apparatus requires regulation of the feed pump 160 so that it can feed a developing solution at a constant pressure.
Such inconveniences further cause necessity of several feed pumps each for one of several supply nozzles when the known apparatus is equipped with several nozzles, which resulting in large size and high cost for the known apparatus.
The known apparatus is also disadvantageous in that the lift from the feed pump 160 to the supply nozzle 110 causes insufficiency of the amount of developing solution.
In addition, the imbalance between the pressure for the feed pump 160 for feeding a developing solution and the opening degree of the valve V0 could cause variation in width of developing solution on a wafer when the developing solution hits the wafer at high pressure at a discharging-starting moment of developing solution.
A purpose of the present invention is to provide a coating method and a coating apparatus with automatic coating-solution flow-rate adjustments during a coating process and high controllability of flow-rate and pressure adjusters in accordance with how a coating-solution supplier is (or coating-solution suppliers are) used, thus achieving compactness in apparatus, uniformity of coating process and economical use of coating solution.
The present invention provides a method of a coating method including the steps of: supplying a processing solution onto surfaces of targets to be processed from a plurality of processing-solution suppliers; adjusting, via a flow-rate adjuster, a flow rate of the processing solution while supplied to each target from the corresponding processing-solution supplier; feeding the processing solution from a processing-solution supply source at a specific pressure via a processing-solution pressure-up feeder; adjusting, via a pressure adjuster, the pressure of the processing solution fed via the processing-solution pressure-up feeder to another specific pressure or more at which the processing solution is fed to the processing-solution suppliers at least when the processing-solution suppliers are operating simultaneously; detecting, via a flow-rate detector, a flow rate of the processing solution supplied via the processing-solution pressure-up feeder; detecting, via a pressure detector, the pressure of the processing solution fed via the processing-solution pressure-up feeder; and controlling the flow-rate adjuster and the pressure adjuster based on prestored control data and detection signals from the flow-rate detector and the pressure detector so that same amount of the processing solution is supplied to the targets to be processed from the processing-solution suppliers.
Moreover, the present invention provides a coating method including the steps of: supplying a processing solution onto a surface of at least one target to be processed from at least one processing-solution supplier, the surface of the target being divided into a plurality of fields; adjusting, via a flow-rate adjuster, a flow rate of the processing solution while supplied to each field on the target while the processing-solution supplier is moving in relative motion to the target; feeding the processing solution from a processing-solution supply source at a specific pressure via a processing-solution pressure-up feeder; adjusting, via a pressure adjuster, the pressure of the processing solution fed via the processing-solution pressure-up feeder to another specific pressure or more at which the processing solution is supplied to all of the fields on the target at least simultaneously; detecting, via a flow-rate detector, a flow rate of the processing solution supplied to each field on the wafer; detecting, via a pressure detector, the pressure of the processing solution fed via the processing-solution pressure-up feeder; and controlling the flow-rate adjuster and the pressure adjuster based on prestored control data and detection signals from the flow-rate detector and the pressure detector so that the processing solution is supplied to each field on the target at a predetermined flow rate from the processing-solution suppliers.
Furthermore, the present invention provides a coating apparatus including: a plurality of processing-solution suppliers to supply a processing solution onto surfaces of a plurality of targets to be processed; a flow-rate adjuster, provided for each processing-solution supplier, to adjust a flow rate of the processing solution while supplied to the targets; a processing-solution pressure-up feeder to feed the processing solution from a processing-solution supply source at a specific pressure to each processing-solution supplier; a pressure adjuster to adjust the pressure of the processing solution fed via the processing-solution pressure-up feeder to another specific pressure or more at which the processing solution is fed to the processing-solution suppliers at least when the processing-solution suppliers are operating simultaneously; a flow-rate detector to detect a flow rate of the processing solution supplied from each processing-solution supplier; a pressure detector to detect the pressure of the processing solution fed via the processing-solution pressure-up feeder; and a controller to control the flow-rate adjuster and the pressure adjuster based on prestored control data and detection signals from the flow-rate detector and the pressure detector so that the same amount of processing solution is supplied to the targets from the processing-solution suppliers.
Moreover, the present invention provides a coating apparatus including: at least one processing-solution supplier having a plurality of processing-solution supplying apertures divided into a plurality of blocks through which a processing solution is supplied onto a surface of at least one target to be processed; a transfer mechanism to move the processing-solution supplier in relative motion to the target; a flow-rate adjuster, provided for each block of the processing-solution supplier, to adjust a flow rate of the processing solution while supplied to the target; a processing-solution pressure-up feeder to feed the processing solution from a processing-solution supply source at a specific pressure to the processing-solution supplier; a pressure adjuster to adjust the pressure of the processing solution fed via the processing-solution pressure-up feeder to another specific pressure or more at which the processing solution is fed at least to one or more of the blocks through which the processing solution is supplied simultaneously; a flow-rate detector to detect a flow rate of the processing solution supplied through each block of the processing-solution supplier; a pressure detector to detect the pressure of the processing solution fed via the processing-solution pressure-up feeder; and a controller to control the flow-rate adjuster and the pressure adjuster based on prestored control data and detection signals from the flow-rate detector and the pressure detector so that a predetermined flow rate of processing solution is supplied to the target through each block of the processing-solution supplier.
Still, furthermore, the present invention provides a processing-solution supplying method including the steps of: increasing a flow rate of a processing solution up to a set constant rate toward a region in the vicinity of an edge of a rotating target to be processed; supplying the processing solution at the set constant rate from the region in the vicinity of the edge to another region in the vicinity of the center of the target; decreasing the flow rate of the processing solution on a specific region between the region in the vicinity of the center of the target to a region in the vicinity of another edge of the target, thus spreading the processing solution over the surface of the target; and decreasing further gradually the flow rate of the processing solution from the specific region to the region in the vicinity of the other edge of the target.